18171618013 has 4 divisors (see below), whose sum is σ = 18173968380. Its totient is φ = 18169267648.

The previous prime is 18171617963. The next prime is 18171618029. The reversal of 18171618013 is 31081617181.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14966586244 + 3205031769 = 122338^2 + 56613^2 .

It is a cyclic number.

It is not a de Polignac number, because 18171618013 - 2²¹ = 18169520861 is a prime.

It is a super-4 number, since 4×18171618013⁴ (a number of 42 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18171618083) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1163548 + ... + 1179061.

It is an arithmetic number, because the mean of its divisors is an integer number (4543492095).

Almost surely, 2^18171618013 is an apocalyptic number.

It is an amenable number.

18171618013 is a deficient number, since it is larger than the sum of its proper divisors (2350367).

18171618013 is an equidigital number, since it uses as much as digits as its factorization.

18171618013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2350366.

The product of its (nonzero) digits is 8064, while the sum is 37.

The spelling of 18171618013 in words is "eighteen billion, one hundred seventy-one million, six hundred eighteen thousand, thirteen".